A 40-year-old construction worker named Tojima Tanzaburo has spent his entire life obsessed with the dream of becoming a Kamen Rider. From childhood through adulthood, he trained his body in seclusion and lived by the heroic ideals he absorbed from the television series, yet he had no enemy to fight. On the verge of abandoning his fantasy, he stumbles into a crime wave where criminals dress as Shocker combatants. He dons a plastic Kamen Rider mask, beats them down, and briefly becomes a local sensation. That act rekindles his purpose, but the situation is far more serious than he realizes. The fake Shocker robbers are being manipulated by a yakuza named Nakao Hachiro, who himself dreams of becoming a Shocker combatant. Worse, the real Shocker organization has been hiding in plain sight all along. Its combatants can instantly transform at the shout of "Ei!", gaining twice the physical ability of an ordinary person, and its monsters, grotesque animal-like beings, command them. Shocker has infiltrated the police and society at large, covering up its own crimes.

Tojima soon meets Okada Yuriko, a 24-year-old high school teacher who idolizes Electro-Wave Human Tackle from Kamen Rider Stronger. She has mastered multiple martial arts and sews her own Tackle costume, determined to be a hero who does not die like the one in the show. Together with Shimamura Ichiyo, a man who lives as Kamen Rider V3 in spirit and uses a V3 Electro Heat Chop, and his younger brother Shimamura Mitsuba, a family restaurant manager who emulates Riderman with a cassette arm, they form a makeshift group. They are later joined by Yukaris, a female Shocker combatant who was sent to spy on them but whose love for Mitsuba breaks her brainwashing, and by Nakao himself, who is transformed into a Shocker combatant against his will and becomes a wandering fighter loyal to his underlings.

The story unfolds as a series of escalating confrontations with Shocker monsters: the cautious strategist Spider Man (human alias Kumota), the megalomaniac Bat Man who drinks blood to spawn new combatants, the plant-wielding Saracenian who infiltrates Yuriko's school, and the aerial fighter Bee Woman. Interspersed are internal conflicts such as a brutal tournament among the heroes themselves to determine who is strongest, a subplot involving Shimamura's sister Futaba who trained under the mysterious Tiger Master to kill her own brother, and a pro-wrestling arc where the former combatant Thunder Raiko uses her love of wrestling to break free of Shocker's control. The group also encounters the enigmatic Tiger Master, a masked female martial artist who becomes their training partner.

The setting is a contemporary Japan where the fictional Shocker is real, but nobody questions why a television show's villain organization actually exists. The heroes do not investigate Shocker's origins or warn the public; they simply fight whenever they encounter it. Tojima, Yuriko, Ichiyo, and the others rely on sheer willpower, improvised techniques, and their fanatical devotion to the Kamen Rider ethos. They shout "Rider Punch!" and "Rider Kick!" as they attack, but their battles are bloody, desperate affairs that leave them battered and sometimes traumatized. Tojima's fixation on becoming a hero gradually pushes him toward psychological breaking points. Yuriko confronts him with the accusation that he is no longer a hero, just a killer. The narrative arc traces his fall and his eventual redefinition of what it means to transform: not into a costumed superhuman, but into someone who stands up for others despite knowing he will fail to save everyone. In the final battle against Shocker's leadership, Tojima is mortally wounded while shielding Yuriko. He says he finally feels like he has transformed. His body is never found, only his mask, which Yuriko holds as a symbol of his conviction. The story closes with children playing at being heroes, suggesting that his spirit endures.

The manga serialized in Monthly Hero's from May 2018, moved to the Comiplex web platform in November 2020 after the magazine ceased publication, and concluded with 18 volumes by May 2026. An anime adaptation aired from October 2025 to March 2026. Throughout its run, the series balanced slapstick comedy with grim psychological drama, using its middle-aged characters to explore the gap between childhood dreams and adult reality, the cost of obsession, and the question of whether a person can be a hero without special powers.